bovine pestivirus infection: a cause of ovulatory disturbance in dairy cows

twelve (experiment i) and four (experiment ii) multiparous dairy cows seronegative to pestivirus were selected and randomly assigned to either a control group which did not become infected or a treatment group in which all cows became infected following intranasal inoculation 9 days before ai. the experimental induction of infection was carried out with 2 ml of non-cytopathic pestivirus (bvd virus) suspension containing 5 log10 tcid50/ml (experiment i) and 4.5 log10 tcid50/ml (experiment ii). in both experiments, the cows were superovulated on day 10±2 of the cycle using the standard procedures. the cows in experiment i were artificially inseminated at 12 and 24 h after the onset of estrus and a non-surgical ova/embryo collection was performed 7 days after ai. in experiment ii, the cows were slaughtered on day 8 after superovulation-induced estrus and the ovaries submitted for gross and histopahological examination including immunohistochemistry. mean (±se) number of ovulatory sized follicles on day of ai and corpora lutea palpated on day 7 after ai were significantly (p